Switch to full app paths

Instead of inserting the path of the apps into the Python app,
the apps are now referenced by their full import path.

This solves name clashes with external or native Python libraries.
Example: Mayan statistics app vs. Python new statistics library.

Every app reference is now prepended with 'mayan.apps'.

Existing config.yml files need to be updated manually.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/mirroring/apps.py

@@ -4,14 +4,14 @@ from django.apps import apps
 from django.db.models.signals import pre_delete, pre_save
 from django.utils.translation import ugettext_lazy as _
 
-from common.apps import MayanAppConfig
+from mayan.apps.common.apps import MayanAppConfig
 
 from .handlers import handler_document_cache_delete, handler_node_cache_delete
 
 
 class MirroringApp(MayanAppConfig):
     has_tests = True
-    name = 'mirroring'
+    name = 'mayan.apps.mirroring'
     verbose_name = _('Mirroring')
 
     def ready(self):